Refrigerating and heat-interchanging apparatus



C. L. BURDICK REFRIGERATING AND HEAT INTERCHANGING APPARATUS Filed Nov.21, 1925 sheets-sheet 1 :y z wlNvgNToR ATTORNEYS 4Dec. l1, 1928.

" c. L. BuRmcK RERIGERATING AND HEAT INTERCHANGING APPARATUS Filed Nov.21, 1925 2 sheets-sheet 2 INVENTOR m .f laz Patented Dec. 1 1, 1.928.

UNITED sTATEs Nr OFFICE.

CHARLES LALOR BURDICK, F NEW YORK, N. Y. l

REFRIGERATING AND HEAT-'mruncnauenve APPARATUS.

Application filed November 21, 1925.` Serial No. b'?0, 512.

This invention relates to apparatus for interehanging heat betweenliquids and has for its object the provision of a heat interchangingapparatus of improved construe-VV Diiiculty has been experienced in thepast in so constructing apparatus for interchanging heat-between li uidsas to secure a sufficiently high rate o heat transfer-with van apparatusoccupying a given amount of space, and as welll in buildingthe-apparatus at a relatively low first cost. Also in many of the priorinstallations the operating and maintenance costs have been 'excessiveAmong the more important factors concerned in the operation of a heatexchaneino` l apparatus which affect the attainment of? th desiredresults are the heat conductivity of the separating mediumg'the velocityat. which the liquids are moved over the surfaces of this medium, andthe viscosity of the liquids Vdealt with.

The importance of high heat .conductivity has always been recognized andwherever it is possible to do so, materials, such for example as copper,are employed for the separatingmedium. Provision for approvvpriatevelocity conditions and for securing rapid heat transfer with'viscous aswell as mobile liquids," however, presents a mene diiiicult problem.

In building heat interchanging apparatus of the type inquestion, it isusual to make the separating medium in the form of one or more tubes orvconduits, the exterior ofthe tubes being submerged in a body of one ofthe liquids and the other liquid being passed through their interior.Assuming the appa- Y ratus to be used for refrigeration' .with theliquid to be cooled passing through the interior of the tubes, when as'olid column of .ofliquid at relatively low velocityv in Contact liquidis passed through the tubes in accordance with the prior practice,.theliquid at the center ofthe column either gives up cxtremelylittle heat,or elsey is cooled ineiiiciently because lthe relatively thin layer withVthe interior surface of the tubeacts asa -heat insulator.: Thisv isparticularly true when oil is the liquid whichit is desired to `cool.

A further source of loss in the operation of such heat exchangers occursona'ccount of the fact that the liquid at the center of each tubeconstitutes a large percentage of the total liquid in the tube and 1t isnecessary transfer conditions to force this relatively large amount ofsub-v medium. Thus a separating medium in the l form of a tube isemployed having one end higher than the other so that liquid will vflowthrough it.. by gravity. Means are provided for continuously maintainingav film of one of the 'liquids on the exterior. surface of this tube anfor eontinuouslymaintain- 4ing a film of the other` liquid ontheinterior surface ofthe tube.- --In the preferred form -of my improvedapparatus a plurality of tubes arranged in the vertical position, orapproximately so, are employed and means are provided 1 for dischargingyone of the liquids onto the exterior surface of the tubes in thinannular streams which flow rapidly downwardlyv over eachtube. Meansarealso of the other liquid into the interior of the upper end of each ofthe tubes. These thin streams ofthe two liquids flow rapidly down ltheirrespective surfaces of the --tubes by gravity and duringthis passage theinter' change of heat between them takes place. This interchange is thusaccomplished under extremelyv effective conditions inasmuch as the twostreams are separated lonlyby the relatively thin walls of the tubeswhich are composed of good heat conducting material, such for example ascopper orsteel depending upon thenature of the materials to be 'treated.i

-' arranged to discharge a thin annular stream Becauseof the factthee-flow of .each

of the liquids takes place in the form of a film or relatively thinstream the only propelling force required is that'of gravitation.

There is no opportunity for the formation of eddy currents in the centerof the conduits asin the case of a solidcolumn vof liquid being forcedthrough a conduit under pressure. The present invention is applicablenot only to the interchange of heat .between two liquids which remain inthe liquid-condition, but' also it may be advantageously employed whenone of the liquids undergoes vaporization during the heat transfer, asfor example, in the cooling of brine in an ice or refrigeration plant bythe vaporization of liquid ammonia. In this case the brine is preferablydischarged onto the interior -surface of the tubes inthe form of a filmor thin stream as before, and means are provided for maintaining a filmof the liquid undergoing vaporization on substantially the entireexterior surface of the' tubes. For this purpose the liquid undergoingvaporization is distributed in a pluralityof zones spaced one above theother, as for example by means of a plurality of vertically spaced trayseach of'which is provided with outlets for discharging a thin annularstream ofliquid onto the exterior of each of the tubes. In this casealso it is important to enclose the plurality of tubes in a chamber soas to v collect the vaporized liquid and ret-urn itto Vintercha-ngingheat'between two liquids both of which remain in the 'liquid form duringthe heat transfer.

Fig. 2 is an enlarged fragmentary vertical section taken through one ofthe tubes to illustrate the details of the liquid distributing devices.

Fig.` 3 is a vertical section of an apparatus for use with two liquidsone of which undergoes vaporization during the heatintcrchange, and

Fig. 4 is an enlarged fragmentary section' showing the liquiddistributing means of the apparatus of Fig. 3. Referring first to Fig. 1of the accompanying drawings, there is here shown a tank 10 having apair of headers 11 and 12 spaced respectively from the top and bottom ofthe tank. These headers therefore form three chambers, the upper chamber13, the

intermediate chamber l 111 and the lower chamber chamber 15. A pluralityof tubes 16 extend vertically between the headers 11 and 12 within theintermediate chamber 14 and the interiors of each of these tubes are infree communication with the upper chamber 13 and the lower chamber- 15.Lower chamber 15 is closed at the bottom by means of a plate 1? uponwhich the tank rests but the upper chamber 13 may be left open or, asshown in Fig. 1, provided with acover 18. This cover may be loosely heldip place and used merely for the exclusion of foreign matter, or it maybe secured tightly in place depending upon the manner in which theapparatusv is employed as will b -seen later. Y

One of theliquids undergoing treatment is fed through a supply pipe 1 8.under the control of valve 19 onto a tray or diaphragm 20 which isplaced near the top of intermediate chamber 14. This* tray 20 hasl a rim35 around its edges to maintain' a pool of liquid thereon and is alsoperforated for the passage therethrough of each of the tubes 16 withopenings 21-(see Fig. 2) slightly larger in diameter than the diameter.of the tubes 16. Through the annular outlets thus provided and'under thehead ofliquid in the pool on the tray the liquid Hows from the tray 20in the form of a film or relatively thin annular stream which passesdown over the entire exterior surface of each of the tubes 16. Thisliquid is collected on the top of bottom header 12 and withdrawn throughthe valve controlled outlet 23.

The other liquid enters upper chamber 13 of the apparatus throughconduit 24 under the control valve 25. The upper end of each ofthe pipes16 is provided with a liquid distributing-device 26. h'Ihis devicecomprises a cap member 27 having a depending collar 28 by which it isremovably held within the tube 16. Packings may be inserted betweencollar 28 and theinterior of the upper end lar from sticking. Anaperture 29 passes through the center of cap 27 and vertically 4below,this aperture a cone shaped member 30 is suspended by preferably three'web members31 which are attached tothe col-y I 105 ,of the tube ifdesired for the'purpose of Asey curing atight joint and to prevent thecol-4 of. the tubes 16 in the form of a iilmf or thin annular stream 32.Thesestreams' passout of the lower' ends of the tubes 16 into the lowerchamber 15 and the liquid collecting therein takes its exit from theapparatus through the valve 33.

In feeding theliquid to the upper chamber 13 valve 2 5 is regulated s0as to maintain a relatively small head of liquid abovel the distributingdevice 26 so that the liquid passes through the apertures 29 entirely under the influence of gravitation. In this case cover 18 need only beloosely held in place or may be omitted entirely. However, if it isdesired to do so, the ycover 18 may be firmly secured to the tank 10 andliquid fed to chamber 13 under pressure.

The two concentric annular streams or films ofliquid passingsimultaneously down the opposite surfaces of the tubes 16 interfilmsandthe very intimate contact of all the liquid with the tubes.Substantially all of the 'heat represented by the difference in ltemperatures between the two liquids less the amountof heat which isabsorbed by conf duction to the tubes of wall 16 is transferred from oneliquid to' the other. Either the warmer or the cooler liquid may becaused to pass through the interior of the tubes'. If

either ofthe liquids have any tendency to cause unavoidable deposits ofscally material upon the surface of the tubes it is convenient to passsuch liquid through the interior' of the tubes because in that case thetubes may be very readily cleaned of their scale. This -is accomplishedby removing the cover 18 and each of the distributing devices 26 andthen introducing some convenient form of tube cleaner.

' Referring now to Figs. 3 and 4 of the accompanying drawings whichillustrate the apparatus of the invention when modified to e'ect thetransfer of heat between two vliquids one of which is undergoingvaporiraa-h tion, the general arrangement of the apparatus is similar tothat of Figs. 1 and 2. The tank 10, upper and lower headers 11 and12,upper and lower chambers 13 and 15, and the arrangement of the tubes 16extending loe-y tween the headers is exactly the same as shown inFig. 1. The liquid distributing devices 26 for delivering liquid in theform of films or thin annular streams to the interiors of the tubes 16are also Constructed as shown in Fi. 2 and mounted in the upper ends ofthe tues 16 the same as in the aps.

'Y l paratus of Fig. 1.

The means for continuously maintaing the films of liquid undergoingvaporization on the exterior surfaces of the tubes are however, subjectto some modification. Thus as is illustrated in Fig. 3 there are rovidedav plurality of transverse trays or iaphragms 34 which are verticallyspaced from the top to the bottom of the intermediate chamber 14 betweenvthe headers 11 and 12,. Each of 0` these headers is provided with a rim35 by which a pool of iquid of substantial depth may be maintainedtherein, and the several trays are provided with perforations 36 for.each of the tubes 16 the perforatlons 36 be ing. slightly larger indiameter than the diameter of the tubes. In this way annular streams ofliquid from the pools which are maintained on eachof vthe trays aredischarged onto the exterior surfaces of the tubes 16. The liquidundergoing vaporization, such for example as ammonia is fed into theapparatus through pipe 37 Vwhich discharges onto the uppermost tray 34.A con' siderable quantity of excess liquid is dis- -charged onto thistray and overliows the rim 35 onto the next tray below. An excess`tically spaced zones. vThe liquid to vdevice 41 which returns ofliquidis discharged from each of the `rims35 of the successive trays 34and Athus on each` of the liquidbeing cooled which in this case it ispreferable to pass through the interiors of the tubes 16 and which istherefore fed to the upper chamber 13 throughthe control valve 38. Bymeans of the spaced trays 34 liquid undergoing vaporization is fed tothe surfaces of the tubes 16 in a pluralit of verccoole after passingdown through the tubes 16 in the ilm-like formations collects in thelower chamber 15 and passes out through the valve controlled outlet 39.

Inasmuch as it is desirable to maintain an excess of liquid lundergoingvaporization on the surfacesof all yof the trays 34; a certain amount ofthis liquid lwill collect on the top of the bottom header 12 andprovision' is made for removing this excess -liquid by means of pipe 40.Pipe40 leads to a lifting the liquid to the su ly pipe 37. vl. evaporized liquid within the intermediate chamber 14 passes in acircuitous path past the rims 35 of the trays which are spaced instaggered relation from the side walls of the tank for this purpose, andrising toward the top of chamber 14 is withdrawn therefrom through thepipe 42.In order to prevent entrained globules of unvaporized'liquidfrom being'drawn out 'through pipe 42 a deflector 43 isprovided justabovethe supply pipe 37 and which can conveniently be constructed in thesame mannerwardly along this surface without inter-4 ruption other thanthat caused by friction, there being no opportunity for the building upof a back pressure caused by eddy currents as is common when a solidcolumn of liquid is forced through a tubular conduit.

The flow of the 4liquid on the exterior of the .tube takes place undersimilar conditions.

Furthermore, the transfer of heat is effected directly through the wallsof the tubes 1-6 from one film of heat-giving liquid .to another'flm ofheat-absorbing liquid. When it is desirable, an adjustment of the thick.

ness of the annular streams lon the exterior and interior respectivelyis made so that the entire available heat corresponding to thedifference of temperature between the liquids will be transferred fromone stream to the other. Inasmuch as onl an annular stream of liquid ispresent within the tubes, the liquid in this stream'is heated or cooledto a maximum or minimum temperature, as the case may be, because theabsence of the lcore of liquid within the annular stream takes away theopportunity for a transfer 'of heat from the annular'stream to thisrelatively large core or body of liquid. f

VThe equipment for using a vaporizing refrigerant differs fromtheequipment using a nonvaporizing refrigerant in that the equipmentusing a vaporiziug refrigerant must have a gas tight chamber between thetube headers. In the case of the non-vaporizing refrigerant, this gastight chamber between the headers is optional depending on thetemperature, vapor ressure and value of the fluid on the outsi e` of thetubes. v Also, for the best operation of the equipment using `avaporizing refrigerant, the trays or headers are preferably to7 be sospaced apart vertically that'the quantity of vaporizing refrigerantwhich can pass through the annular openings around the conduits will notbe completely vaporized beforeit can reach the next t-ray below or thelower en d of the conduits. If the annular opening-around the conduitsand the length of the conduits are such that a sulficient amount ofvaporizing refrigerant can pass through the annual opening so as tosupply the full length of the conduit with a film, one top tray issatisfactory. If the length of the conduits is such that a suliicientamount of vaporizing refrigerant does not pass through the annularopening around the conduits so as to provide a lm of vaporizingrefrigerant the full length of the conduit'svthen a pliirality of traysis preferable. In one form ofthe invention the trays are preferablyprovided with` segmented `openings arranged in a staggered manner sothat the segmental openings on successive trays are4 opposite hand thusallowing the vaporizing-.refrigerant in excess of that which gassesthrough the annular `openings of the rst tray to flow over the edge ofthesegmental openings to the next lower tray.

The length of the 'conduits can also be sol proportioned so as to enablea sufficient quantity of va orizing refrigerant to be supplied to theinslde of the conduits and maintain a film of vaporizin refrigerant thefull length of the inside of t e conduits` This arrangement of theinvention necessitates there being a fas tight chamber connected to theinside o the tubes in a manner similar to the connections shown in theattached drawings on the gas tight chamber around the outside of thetubes.

When a non-vaporizing refrigerant is used it can be supplied to eitherthe inside or the outside of the tubes. ASince there will be no\v'aporization there will be no loss of liquid from the films and thetop tray will supply a suilicient amount of non-vaporizing refrigerantto run the whole length of the tube.' e

Thus, by constructing the apparatus in accordance with the principles ofthe present invention the transfer of heat is so effectively made thatthe size of the apparatusv for il a given installation is relatlvelysmall, thusv for separating said liquids having one end p' higher thanthe other so that liquid will' flow through by gravity, mea-ns fordischarging one of said liquids in an annular stream onto .the exteriorof each ofsaid tubes, and A means including an apertured cap fitted intothe upper end of each of said tubes and supporting a cone-shaped memberwithin the tube to receive liquid passing through the aperture in thecap and discharge itin an annular stream onto the interior surface ofthe tube.

2. In an apparatus for interchanging heat between two liquids, a tank4having a pairof headers spaced respcctivelyvfro'mthe top and bottomthereof and 4forming an upper, a lower and an intermediate chamber, aplurality of vertical Atubes extendingbetween thev headers through theintermedi ate chamber and having their interiors communicating with theupper and lower jl chambers, a transverse tray withinthe intermediatechamber near the top thereof, said tray having perforations foreach of Ysaid tubes for delivering an annular stream -o'f liquid onto theexterior of each tube,

means for supplying liquid to said tray, means for withdrawing saidliquid fromthe bottom of the intermediate chamber, an

aperturedcap for the end of each tube *in the upper chamber and:icone-shaped memberV disposed belowv said aperture for directing theliquid passing through the yaperture in an annular stream against ltheinterior surface of the tube, means/forsupplying liquid to the upperchamber, and means for withdrawing said liquid from the lower .In anapparatus for intel-changing'- heat between two liquids one of which isundergoing vaporization, a plurality of tubes for separating saidliquids having one end higher than the other so that liquid will flowthrough by gravity, means for distributing the liquid undergoingvaporiza- I vtion on the exterior surfaces of the tubes in a pluralityof spaced vertical zones, means for distributing the other liquid in afilm on the interior surfaces of saidtubes, and means for collecting thevaporized liquid.

4. In an apparatus for interchanging heat between two liquids one ofwhich is undergoing 'vaporizatiom a plurality of tubes for separatingthe liquids having one end higher than the other so that liquid willflow through by gravity, means for discharging liquid undergoingvaporization in a thin annular stream on the exterior of each tube atspaced intervals from the top to the bottom thereof, means for distribueing the other liquid in a film on the interior of each of said tubes,and means for collecting the vaporized liquid.

5. In an apparatus for interchanging heat between two liquids one ofwhich is undergoing vaporization, a plurality of tubes for separatingthe liquids having one end higher than the other so that liquid williiow t rough by gravity, means for discharging t e liquid undergoingvaporization in a thin annular stream on the exterior of each tube i atspaced intervals from the top to the bottom thereof, means including acone-shaped member for directing a thn annular stream of the otherliquid onto t-he interior surface of each tube, and means for collectingthe vaporized-liquid.

6. In an apparatus for 'interchanging heat between two liquids one ofwhich is undergoing vaporization, a tank having a pair l of headersspaced respectively from the top and bottom thereof and forming an upperchamber, a lower chamber and an intermediate chamber, a plurality oftubes extending between the headers through the intermediate chamber andhaving their interiors communicating with the upper and lower chambers,a plurality of vertically spaced trays arranged within the intermediatechamber and having outlets for distributing the liquid to be vaporizedonto the exterior surfaces of said tubes, means for maintaining a poolof liquid to be vaporized upon each tray, means for withdrawing thevaporized liquid from thev intermediate chamber, means associated withthe upper end of each of the tubes inthe upper chamber for dischargin athin lannular stream of iiquid onto the interior surface of each tube,means for supplying liquid to said chamber, and means for witherchambers, a plurality of vertically spaced trays larranged Within' theintermediate chamber-and havino' outlets for distributing liquid to bevaporized to the exterior surfaces of the'tubes, said trays having meansfor delivering liquid to be vaporized from one tray to the next lowertray, means for:l

supplying an excess of li uid to be vaporized to an upper tray, means orreturning liquid remaining unvaporized from the bottom of theintermediate chamber to an upper tray therein, means for withdrawingvaporized liquid from the intermediate chamber, means associated withthe up er ends of thev tubes within the upper cham er 'for dischargin athin `annular stream of liquid onto the 1nterior surface of each tube,means for supi plying liquid to said chamber, and means for withdrawingsaid liquid ,from the lower chamber.

8. In heat exchange apparatus employingl upright tubes, substantiallycone-shaped liquid distributing members the upper end portions of saitubes.

ositioned in 9. In heat exchange apparatusemploying 1 upright tubes,apertured cap members positioned adjacent the upper ends of said tubes,and liquid distributing members depending rom said cap members andextending linto the upper end portions of said tubes.

10. In heat exchange apparatusfmploying upright tubes, cap mem ershaving substantially centrally disposed apertures there in positionedadjacent the upper ends of said tubes, and substantially cone-shapedliquid distributing members positioned below said cap memberssubstantially concentric with the apertures in said cap members.

In `testimony whereof I aiiix my signature.

CHARLES LALoR BURDICK.

